1. The Field of the Invention
The present invention generally relates to computing devices and their thermal, acoustic, and electromagnetic properties. More specifically, the present invention relates to controlling thermal, acoustic, and/or electromagnetic properties or characteristics of a computing device, while reducing costs associated with manufacturing such a computing device.
2. Background and Relevant Art
In recent years, there has been significant development in computer technology, ranging from advances in server design, personal and office computers, laptops, personal digital assistants, or the like. These computing devices provide individuals and businesses alike with the ability to perform various functions, obtain entertainment, perform word processing, develop graphics, or the like. Further, many computing devices are capable of providing multimedia entertainment to a viewer, such as set-top boxes, digital video recorders (DVR), personal video recorders (PVR), or the like.
Generally, each type of computing device is designed to operate within a given ambient temperature. For instance, many set-top boxes are designed to operate at an ambient temperature in a range from about 35° C. to about 40° C. To enable operation at such temperatures, computing devices are configured to radiate the heat energy generated by various internal electrical components to the environment external to the computing device. For instance, many computing devices include a power supply that generates a significant amount of heat energy that must be dissipated from the computing device to protect the internal electrical components from overheating.
Additionally, many computing devices include microprocessors that perform various calculations and control the operation of the computing device. As the microprocessor performs such functions, the processor generates heat energy. To dissipate the heat energy generated by the microprocessor, many computing devices include one or more heat sinks mounted to the microprocessor. Each heat sink transfers a portion of the heat generated by the microprocessor to the air surrounding the heat sink. The air surrounding the heat sink is often moved to enhance the convective transfer of heat to the air. In the absence of the forced advection of air in the computing device, the air can become stagnant, which reduces the convective transfer of heat from the heat sink.
Many computing devices utilize fans to draw relatively cool air into the housing of the computing device and expel relatively warm air from the housing. For instance, in many home computers, a first fan is mounted to receive air directly from outside the housing of the computing device and a second fan mounted to the processor and/or heat sink. In such a case, the cooler air is drawn into the computing device, passes over a heat sink mounted to the microprocessor, and is expelled from the computing device. Other computing devices include fans that expel the air from the internal area of the housing.
Unfortunately, such two-fan systems do not efficiently eliminate hot spots within the internal area of the computing device. For instance, the air drawn into and expelled from the housing may not evenly cool internal components or internal areas of the computer, resulting in components or internal areas of the computing device being cooled to a lesser degree than other components or areas of the computing device. Consequently, the components within these hot spots may become damaged from exposure to excessive heat.
Additionally, computing devices with fans mounted to a wall of the housing generate acoustic noise as the fans operate. In an office setting, such acoustic noise may be acceptable to the owner or operator of the computing device. However, within a home environment, such acoustic noise generated by the fan may become irritating to individuals as they utilize the computing device. Illustratively, where the computing device is a set-top box, DVR, or PVR, the acoustic noise associated with the computing device can become distracting to viewers watching broadcast programming that is presented via an associated display device. Furthermore, the inclusion of two fans within a computing device is expensive.
In addition to the above problems with existing computing devices, computing devices generate electromagnetic energy that radiates from the computing device. Such electromagnetic energy can interfere with other electronic devices located in close proximity to the computing device. The amount of such electromagnetic interference (EMI) allowable by each computing device is controlled by government standards. Consequently, computing devices are often designed to suppress, to varying degrees, the EMI generated by the internal components of the computing devices. Typically, the processor of a computing device generates a significant portion of the EMI among the internal components of the computing device.
In light of the above, it would be beneficial to develop a computing device that is capable of eliminating hot spots within the computing device, reducing acoustic noise associated with the cooling mechanisms of the computing device, and/or eliminate or prevent excessive EMI, and do so in a simple, efficient, and cost-effective manner.